1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to a method and system for facilitating percutaneous aortic valve replacement.
Patients suffering from significant aortic valve disease are frequently treated by aortic valve replacement procedures. While most aortic valve replacements are still performed in open chest procedures, recently there have been significant advances in minimally invasive aortic valve replacement where the valve is introduced through either a transapical approach (minimally invasive) or a transvascular (percutaneous) approach over the aortic arch.
Both transapical and transvascular PAV procedures are “beating heart” procedures where continuing blood flow from the left ventricle into the aorta creates hemodynamic forces on the replacement valves and the tools used in the replacement procedures. In an effort to control the hemodynamic forces and to stabilize the tools and valve used for replacement, that the use of a “temporary aortic valve” (TAV) has recently been proposed. As described in commonly owned published US Patent Applications US 2009/0030503 and US 2009/0030510, the full disclosures of which are incorporated herein by reference, a catheter is intravascularly introduced over the aortic arch to position a balloon assembly in the ascending aorta just above the Sinus of Valsalva. The balloon assembly includes three equally sized balloons disposed in parallel about the distal tip of the catheter, and the inflated balloons together limit retrograde blood flow (flow in the direction from the aorta toward the aortic valve) during diastole, thus limiting disturbance of the tools and/or valves located in the aortic valve annulus during the procedure. The balloon inflation only partially occludes the aortic lumen in order to both allow antegrade flow during systole and to permit a limited retrograde flow during diastole in order to perfuse the coronary vasculature through the Sinus of Valsalva and to protect the left ventricle from excessive volume overload.
While of great potential benefit, the use of the balloon structures described in the prior patent applications is necessarily a compromise between resistance to regurgitation during diastole and forward blood flow patency through the aorta during systole. Also, the balloon structures and protocols described in the published patent applications do not provide for adjusting the extent of occlusion of the aorta as may be optimal during different stages of the valve removal and replacement procedures.
For these reasons, it would be desirable to provide methods and systems for occluding the aorta to limit aortic regurgitation during valve repair and replacement procedures where the degree of aortic occlusion can be adjusted during the procedure, both in synchronizing with the systolic and diastolic portions of the heartbeat and during different segments of the procedure, such as valve ablation, valve removal, replacement valve positioning, replacement valve assembly, and the like. At least some of these objectives will be met by the inventions described herein below.
2. Description of the Background Art
US Patent Publications US 2009/0030503 and US 2009/0030510 have been described above. The use of an intra-aortic balloon pump during coronary interventions on patients having complicated left main stenoses is described in Mishra, et al., (2006) Am J Cardiol 98:608-612. U.S. Patent Publication US 2008/0147160 describes a catheter having an expandable cage structure located in the Sinus of Valsalva for stabilizing a guide wire in transapical valve replacement procedures. The use of a “parachute” valve for providing a temporary aortic valve is described in Vandenberghe, et al., (2008) ASAIO J 54:547-577.